(S)-2-((3S,8S,9S,10R,13S,14S,17R)-3-((tert-butyldimethylsilyl)oxy)-10,13-dimethyl-2,3,4,7,8,9,10,11,12,13,14,15,16,17-tetradecahydro-1H-cyclopenta[a]phenanthren-17-yl)propanal

(20S)-3β-(t-butyldimethylsilyloxy)-20-oxomethylpregn-5-ene